Liquid Crystals Comprising Cyclopentane Groups

ABSTRACT

Provided are liquid crystal compounds and mixtures incorporating the same. The liquid crystal compounds of the invention generally comprise a cyclopentane group and at least two other rings. In one embodiment, the liquid crystal compounds of the invention comprise a cyclopentane group and at least two other rings, one of which is a fused ring system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 61/027,230, filed Feb. 8, 2008, which is hereby incorporated byreference to the extent not inconsistent with the disclosure herewith.

BACKGROUND OF THE INVENTION

Liquid crystal displays use mixtures of liquid crystals having desiredmaterial properties such as operating temperature range, thermalstability, light stability, switching time, and contrast ratio. Theproperties of the mixtures and devices are determined by theconstituents of the mixtures.

The demand for liquid crystal displays having improved performance hasincreased. In particular, liquid crystal mixtures having low thresholdvoltage are desired, especially for display applications. The thresholdvoltage is the amount of voltage needed to apply across a pixel toproduce a response. Addressing pixels with lower voltages allowssimplification of the electronics used, resulting in the possibility forspace and weight savings. The threshold voltage is inverselyproportional to the dielectric anisotropy of the mixture. Therefore, oneway to produce a liquid crystal mixture having a low threshold voltageis the use of mixtures having a large (positive or negative) dielectricconstant.

U.S. Pat. No. 5,759,443, U.S. Pat. No. 4,873,019, CN 1928001 A, and EPpatent application EP0789067A1 disclose certain compounds havingcyclopentyl groups.

There is a continuing need in the art for improved liquid crystalcompounds and mixtures.

BRIEF SUMMARY OF THE INVENTION

Provided are liquid crystal compounds and mixtures incorporating thesame. The liquid crystal compounds of the invention generally comprise acyclopentane group and at least two other rings. In one embodiment, theliquid crystal compounds of the invention comprise a cyclopentane groupand at least two other rings, one of which is a fused ring system. Inone embodiment, the liquid crystal compounds of the invention comprise aterminal cyclopentane group and at least two other rings, one of whichis a fused ring system. More specifically, compounds of the inventionhave general Formula I:

wherein

-   R is selected from the group consisting of H and unsubstituted or    substituted alkyl each having 1-12 carbon atoms wherein the    substitutions are independently one or more of halogen or CN,    wherein one or more CH₂ groups of the alkyl groups may independently    be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— or    —CH═CH—, provided that heteroatoms are not connected directly,    except as permitted in the listed groups;-   A and B are each independently selected from the group consisting    of: 1,4-cyclohexyl, in which one CH2 or two not directly linked CH2    can be replaced by O or S; 1,4-cyclohexenyl; piperidine-1,4-diyl;    1,4-bicyclo[2,2,2]octylene; 1,4-phenyl; pyridin-5,2-dyl;    pyrimidin-5,2-diyl; naphthalene-2,6-diyl;    trans-decahydronaphthalene-2,6-diyl; tetrahydronaphthalene-2,6-diyl;    indane; indene; phenanthryl; and dibenzofuran, which may each    independently in each instance be substituted with one or more    halogens and/or one or more X1-X4 substitutents;-   Z1 is a single bond or C1-7 unsubstituted or substituted alkylene,    wherein the substitutions are independently one or more of halogen    or CN, wherein one or more CH₂ groups of the alkyl groups may each    independently be replaced by —O—, —S—, —CO—O—, —O—CO—, —O—CO—O— or    —CH═CH— provided that heteroatoms are not connected directly to each    other except as permitted in the listed groups;-   Z2 and Z3 are each independently selected from the group consisting    of: a single bond, —(CH₂)₂—, —(CH₂)₄—, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—,    CF₂O, OCF₂, CF₂CF₂, CF═CF, CH₂CF₂, CF₂CH₂, OCF2CF2O, C2H4CF2O,    CH2CF2OCH2, CH2OCF2CH2, OCF2C2H4, C3H6O, OC3H6, C2H4OCH2, CH2OC2H4,    CH₄O, OCH₂, —CH═CH—, —C≡C—, and COO;-   n, m and K are each independently 0, 1, or 2, and m+K+n≧2;-   X1, X2, X3, and X4 are each independently selected from the group    consisting of: H, F, Cl, CF3, CHF2, OCF3, OCF2H and CN;-   Y is independently selected from the group consisting of: H, F, Cl,    CN, NCS, OCHF₂, CHF₂, OCF₃, OCF2CF3, CF₃, C₁₋₂₀ alkyl, C₁₋₂₀ alkoxy,    C₁₋₂₀ alkenyl, and C₁₋₂₀ alkenyloxy, wherein the alkyl, alkoxy,    alkenyl, and alkenyloxy groups may be independently substituted by    one or more halogens;-   wherein one or more hydrogen atoms in Formula I may be replaced with    deuterium;

provided that when R═H and Y has less than 2 carbon atoms and X3, X4 areH or when R═H and Y has two or more carbon atoms and Z1 has more than 3carbon atoms, there must be a fused ring system present in the compoundor one of Z1, Z2 and Z3 must be selected from the group consisting of:C1-C3 alkylene, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—, CF₂O, OCF₂, CF₂CF₂, CF═CF,CH₂CF₂, CF₂CH₂, OCF2CF2O, C2H4CF2O, CH2CF2OCH2, CH2OCF2CH2, OCF2C2H4,C3H6O, OC3H6, C2H4OCH2, CH2OC2H4, and —CH═CH—;

-   and provided that when R is not H and Y does not contain a —CF2-    group, either one of A and B is selected from the group consisting    of: 1,4-cyclohexene, in which one or two not directly linked CH2    groups can be replaced by O or S; Pyridin-5,2-dyl;    pyrimidin-5,2-diyl; indane; indene; phenanthryl, and dibenzofuran;    or one of Z1, Z2 and Z3 must be selected from the group consisting    of: —(CH₂)₄—, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—, CF₂O, OCF₂, CF₂CF₂,    CF═CF, CH₂CF₂, CF₂CH₂, OCF2CF2O, C2H4CF2O, CH2CF2OCH2, CH2OCF2CH2,    OCF2C2H4, C3H6O, OC3H6, C2H4OCH2, CH2OC2H4, —CH═CH—, and —C≡C—.-   In an embodiment, X1, X2, X3, and X4 are each independently selected    from the group consisting of: H, F, Cl, CF3, CHF2 and CN.

If not specified, any group, for example a ring structure, may beattached in any suitable location. If there are two or more rings linkedtogether, for example, when n, m or k is not 0, it is noted that each ofthe rings may be the same of different. As an example of this, when n is2, the two “A” rings do not need to be the same, although they may be incertain embodiments. When used herein, “indane” means:

which is attached to the remainder of the structure in any suitablelocation(s). When used herein, “indene” means:

which is attached to the remainder of the structure in any suitablelocation(s).

As used herein, a “single bond” as a variable means that there is adirect linkage between two structures. For example, if Z1 is a singlebond and n is 1, there is a direct linkage between the cyclopentane ringand the A ring. As used herein, a “fused ring system” has at least tworings joined together at at least two atoms. 1,4-bicyclo[2.2.2]octylene;naphthalene-2,6-diyl; decahydronaphthalene-2,6-diyl;tetrahydronaphthalene-2,6-diyl; indane; indene; phenanthryl; anddibenzofuran are all examples of fused ring systems. As used herein,halogen means fluorine, chlorine, bromine or iodine.

In one embodiment, there is at least one fused ring in a compound of theinvention. In one embodiment, a compound of the invention is one of I-11through I-17. In one embodiment, a compound of the invention is one ofI-23 through I-27. In one embodiment, a compound of the invention is oneof I-33 through I-35. In an embodiment, a compound of the invention isone of I-36 through I-47. In one embodiment, a compound of the inventionhas R═H and a fused ring system.

In an embodiment, one or more hydrogen atoms on one or more rings isreplaced with deuterium. In an embodiment, one or more hydrogen atoms ona non-ring structure is replaced with deuterium.

In separate embodiments, the cyclopentene ring has one of the structuresbelow:

All possible locations of one or more deuterium substitution forhydrogen in the structures shown and described herein are intended to beincluded to the same extent as if they were individually shown.

DETAILED DESCRIPTION OF THE INVENTION

The following non-limiting description provides examples of someembodiments of the invention.

The use of one or more compounds of the invention in mixtures havingdesired properties for various liquid crystal applications is known toone of ordinary skill in the art without undue experimentation.

Devices comprising one or more compounds of the invention can be madeand operated by one of ordinary skill in the art without undueexperimentation.

The description herein provides some additional exemplary embodiments ofthe invention and variables which can be separate or combined togetherin all possible permutations, independently and in combination, toformulate compounds of the invention.

The compounds of the invention have a high dielectric constant which maybe positive or negative. The use of compounds and mixtures havingnegative or positive dielectric constants is known in the art. In someembodiments of the invention, the compounds have positive dielectricconstant at least 8. In some embodiments of the invention, the compoundshave a negative dielectric constant of −2 or less. Larger positive andlarger negative numbers are desired.

Positive Dielectric Constant Compounds

Specific particular embodiments of compounds of the invention havingpositive dielectric constants are shown below in structures I-1 throughI-17, where the variables have the following definitions:

-   Y is independently selected from the group consisting of: F, Cl,    CF3, OCF3, OCHF2, OCF2CF3, —OCF═CF2, OCHFCF3, OCF2CF═CF2 ;-   X1, X2, X3, X4 are each, independently of one another, H or F;-   Z is independently selected from the group consisting of: single    bond, —C2H4-, —CF2O—, —CF═CF—, —C2F4-; —CO2-; —C4H8-, —C2H4CF2O—,    —OCF2CF2O—, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—; and-   R is C1-12 alkyl or H.

Negative Dielectric Constant Compounds

Specific particular embodiments of compounds of the invention havingpositive dielectric constants are shown below in structures I-18 throughI-47, where the variables have the following definitions:

-   R is H or C1-C7 n-alkyl;-   R′ is C1-C7 n-alkyl or C1-C7 Alkyloxy;-   X1 and X2 are each independently selected from the group consisting    of F, Cl, CF3, CHF2, OCF3 and OCF2H;-   X3, X4, X5 and X6 are each independently H or F;-   Z is independently single bond, —C2H4-, —C4H8-, —CF2O—, —CF═CF—,    —C2F4-, C2H4CF2O or —CO2-.

Mixtures

As known in the art, there are typically many components of liquidcrystal mixtures, as determined by the desired use of the mixture. Thecomposition of the liquid crystal mixtures of the invention can bedetermined by one having ordinary skill in the art without undueexperimentation. The addition of one or more compounds of the inventionin liquid crystal mixtures improves the properties of the mixture,including lowering threshold voltage, increasing switching speed andother properties which are known in the art.

Positive Dielectric Constant Mixture

The compounds of the invention may be used as components in any desiredliquid crystal mixture, such as those mixtures known in the art. In oneembodiment, the liquid crystal mixture comprises one or more compoundsof Formula I. In one embodiment, the liquid crystal mixture has positivedielectric constant. In one embodiment, the liquid crystal mixturehaving positive dielectric constant comprises one or more compounds ofFormula I-1 through I-17.

The mixture may include one or more compounds of Formula I and one ormore compounds of Formula II-XVI:

in which the individual variables have the following definitions:

-   R is C1-C9 n-alkyl, C1-C9alkoxy, C1-C9oxaalkyl, C1-C9fluoroalkyl or    C1-C9alkenyl;-   X is F, Cl, halogenated C1-C6 alkyl, halogenated C1-C6 alkenyl,    halogenated C1-C6 alkenyloxy or halogenated C1-C6 alkoxy;-   Z is —C2H4, —C4H8-, —CH═CH—, —CH2O—, —COO—, —OCH2-, —OCF2-, —CF2O—,    —CF═CF—, —C2F4, —CH2CF2- or CF2CH2-;-   Y1, Y2, Y3 and Y4 are each, independently of one another, H or F;    and-   r is 0, 1 or 2; and k is 0 or 1, provided that if both r and k    appear in the same formula, r+k≧2

Additional specific examples of compounds which may be included in amixture are shown below where R is as defined for compounds II-XVI:

In each of the formulas shown herein, the structure:

may have any of the following formulas:

In other embodiments, the mixture may comprise one or more compounds ofFormula I and one or more compounds selected from the group consistingof compounds of the structure below XVII-XXIII.

where the variables have the following definitions:

-   R1 and R2 are each independently C1-C9 n-alkyl, C1-C9 alkoxy, C1-C9    oxaalkyl, or C1-C9 alkenyl;

Y1, Y2, Y3 and Y4 are each, independently of one another, H or F, and ris 0, 1 or 2.

Negative Dielectric Constant Mixtures

In one embodiment, the liquid crystal mixture has negative dielectricconstant. In one embodiment, the liquid crystal mixture having negativedielectric constant comprises one or more compound of Formula I-18through I-47. In another embodiment, the liquid crystal mixture havingnegative dielectric constant comprises one or more compounds of FormulaI, such as I-18 to I-47 and additionally comprises a useful amount ofone or more compounds selected from the group consisting of compounds ofthe general formulae XXIV to XLIV, where the variables are as definedbelow:

-   R is C1-C8 n-alkyl, C1-C8 alkoxy, C1-C8 alkenyl or C1-C8 alkenyloxy;-   R′ is C1-C8 alkyl, C1-C8 alkoxy, C1-C8 alkenyl or C1-C8 alkenyloxy;-   X1, X2, X3, X4, X5 and X6 are independently selected from the group    consisting of: H, F, Cl, CHF2, CF3, OCF3 and OCHF2; with the proviso    that at least two from X1 to X6 are F, Cl, CHF2 or CF3;-   Z is independently selected from the group consisting of: single    bond, —C2H4-, —C4H8-, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—, —CF2O—, —OCF2-,    —CF═CF—, —C2F4-, —C2H4CF2O—, OCF2C2H4 and —CO2-;-   r is 0, 1 or 2; k is 0 or 1, providing that r+k≧2.

In other specific embodiments, the negative dielectric constant mixturemay comprise one or more compounds of Formula I and one or morecompounds selected from the group consisting of compounds of formulasXLV-XLVIII below.

in which the individual variables have the following definitions:

-   R1 and R2 are each independently C1-C8 n-alkyl, C1-C8 alkoxy, C1-C8    oxaalkyl, C1-C8 alkenyl, or C1-C8 alkenyoxy;-   X1, X2, X3, and X4 are H or F, provided that only one of X1, X2, X3,    and X4 may be F in the same compound;-   r is 1 or 2; k is 1 or 2.

The compounds of the invention may be used in any useful amount in aliquid crystal mixture, including less than 0.1% by weight of the totalcomposition; less than 0.5% by weight of the total composition; lessthan 1% by weight of the total composition, less than 3% by weight ofthe total composition; less than 5% by weight of the total composition;less than 7% by weight of the total composition; less than 10% by weightof the total composition; less than 20% by weight of the totalcomposition; less than 25% by weight of the total composition; less than30% by weight of the total composition; less than 35% by weight of thetotal composition; less than 40% by weight of the total composition;less than 50% by weight of the total composition; and any other usefulamount.

In one embodiment, there is between 0.5% and 80% of one or morecompounds of Formula I. In one embodiment, there is between 0.5% and 80%of one or more compounds of Formula I-1 through I-17. In one embodiment,there is between 0.5% and 80% of one or more compounds of Formula I-18through I-35. In one embodiment, there is between 0.5% and 80% of one ormore compounds of Formula I, and between 0.5% and 80% or one or morecompounds of a compound of formula II-XVI In one embodiment, there isbetween 0.5% and 80% of one or more compounds of Formula I, and between0.5% and 80% of one or more compounds of Formula XVII-XXIII. In oneembodiment, there is between 0.5% and 80% of one or more compounds ofFormula I, between 0.5% and 80% or one or more compounds of FormulaII-XVI, and between 0.5% and 80% of one or more compounds of FormulaXVII-XXIII. In one embodiment, there is between 0.5% and 80% of one ormore compounds of Formula I, and between 0.5% and 80% or one or morecompounds of a compound of formula XXIV-XLIV. In one embodiment, thereis between 0.5% and 80% of one or more compounds of Formula I, andbetween 0.5% and 80% of one or more compounds of Formula XLV-XLVIII. Inone embodiment, there is between 0.5% and 80% of one or more compoundsof Formula I, between 0.5% and 80% or one or more compounds of FormulaXXIV-XLIV, and between 0.5% and 80% of one or more compounds of FormulaXLV-XLVIII. There may be other components, as known in the art.

Synthesis

The following describes exemplary synthesis reactions for compounds ofthe invention. Conditions for such as reaction are well-known to one ofordinary skill in the art. The synthesis of compounds of the inventionnot specifically exemplified here can be carried out by one of ordinaryskill in the art without undue experimentation using methods known inthe art.

Experimental Synthesis of2-Cyclopentyl-6-(3,4,5-trifluorophenyl)naphthalene Synthesis of1-(6-methoxynaphthalene-2-yl)cyclopentanol (Compound 1)

Grignard reagent was prepared from 6-methoxy-2-bromonaphthalene, dry Mg,a crystal of iodine and a drop of 1,2-dibromoethane in dry THF. Thismixture was then cooled in an ice-sodium chloride bath, a solution ofdried cyclopentanone dry THF was added drop wise via syringe. Theresultant reaction mixture was then slowly warmed to room temperature.Then refluxed for additional 10 hours and cooled to room temperature,added to ice cold Hcl and extracted using ethyl acetate. The combinedorganic extracts were washed with sat. NH₄Cl solution and dried overMgSO₄. The crude product obtained was passed through a column ofsilicagel using 15% EA in hexane as eluent. Yield of the product: 70%.

2-Cyclopentenyl-6-methoxynaphthalene (Compound 2)

A solution of compound 1 in dry benzene, and a catalytic amount (2 wt %)of p-toluene-sulfonic acid were placed in a round-bottomed flask. Theresulting solution was then heated at 50 C for 15 minutes, the reactionwas complete, and the resulting solution was cooled to room temperature,passed through a short pad of silicagel. Yield was almost quantitative,the product obtained was pure enough which was directly used for thenext reaction.

2-Cyclopentyl-6-methoxynaphthalene (Compound 3)

To a solution of compound 2 in ethyl acetate was added a catalyticamount (5 wt %) of 5% Pd-C, the resulting solution was continuedstirring vigorously until the reaction is complete. Yield was almostquantitative. The product obtained was pure enough, which was directlyused for the next reaction.

6-Cyclopentylnaphthalen-2-ol (Compound 4)

A solution of compound 3 in dry dicloromethane was cooled to −78 C indry ice and acetone under argon. To this with stirring, a solution ofBBr₃ in dicloromethane was added dropwise and the resulting solution wascontinued stirring for additional 2 hours at this temperature andallowed to warm to room temperature overnight. The resultant solutionwas extracted using ethyl acetate, the crude product was crystallizedfrom a mixture of methanol and hexane. Yield: 92%.

6-Cyclopentylnaphthalen-2-yl trifluoromethylsulfonate (Compound 5)

A solution of compound 4 and pyridine in dry dichloromethane was cooledto 5 C using ice bath. To this with stirring, a solution of triflicanhydride in dichloromethane was added dropwise which was allowed towarm to room temperature, and continued stirring for additional 2 hours.The resultant solution was extracted using ethyl acetate, the productobtained was a low melting solid, which was directly used for the nextstep. Yield: 95%.

2-Cyclopentyl-6-(3,4,5-trifluorophenyl)naphthalene (Compound 6)

Into a flame dried 100 ml round-bottomed flask with a magnetic stir bar,was charged with compound 5 (1.0 g, 2.9 mMol), 3,4,5-trifluorophenylboronic acid (0.56 g, 3.19 mMol), 20 mL toluene, 2M K₂CO₃ (20 mL),Bu₄NBr (25 mg) and the mixture flushed with argon for 10 min.[Pd(PPh₃)₄] (0.1 g) was added and the mixture heated under argon at ˜85°C. for 12 h, with vigorous stirring. After cooling to room temperature,25 mL water was added, extracted with 3×10 mL ethyl acetate, the organicextracts dried over MgSO₄, and the crude product was then passed througha column of silica gel using hexane as eluent, also crystallized fromhexane. Yield, 0.89 g (94%).

Synthesis of2-(Cyclopentylethyl)-6-(3,4,5-trifluorophenyl)naphthalene 1.6-(3,4,5-trifluorophenyl)naphthalene-2-ol (Compound 1)

A flame dried 500 ml round-bottomed flask with a magnetic stir bar, wascharged with 6-hydroxy-2-bromonaphthalene (8.0 g, 35.89 mMol),3,4,5-trifluorophenyl boronic acid (6.9 g, 39.5 mMol), 75 mL toluene, 2MK₂CO₃ (80 mL), Bu₄NBr (50 mg) and the mixture flushed with argon for 10min. [Pd(PPh₃)₄] (0.5 g) was added and the mixture heated under argon at˜85° C. overnight, with vigorous stirring. After cooling to roomtemperature, 50 mL water was added, extracted with 3×25 mL ethylacetate, the organic extracts dried over MgSO₄, and the crude productwas then crystallized from a mixture of hexane and few drops ofmethanol. Yield: 8 g (87%).

6-(3,4,5-trifluorophenyl)naphthalene-2-yl trifluoromethylsulfonate(Compound 2)

A solution of compound 1 and pyridine in dry dichloromethane was cooledto 5 C using ice bath. To this with stirring, a solution of triflicanhydride in dichloromethane was added drop wise which is allowed towarm to room temperature, and continued stirring for additional 2 hours.The resultant solution was extracted using ethyl acetate, the productobtained was crystallized from dichloromethane and hexane mixture.Yield: 90%.

1-((6-(3,4,5-trifluorophenyl)naphthalen-2-yl)ethynyl)cyclopentanol(Compound 3)

To a solution of triflet (compound 2) and 1-ethynylcyclopentanol in dryDMF under argon, Pd(PPh₃)₄, Cul and triethylamine were successivelyadded, and the reaction mixture was stirred overnight at roomtemperature. The mixture was then diluted with EtOAc, washed with waterand dried over MgSO4. Yield: 93%.

2-(Cyclopentylethynyl)-6-(3,4,5-trifluorophenyl)naphthalene (Compound 4)

A solution of compound 3 in dry benzene, and a catalytic amount (2 wt %)of p-toluene-sulfonic acid were placed in a round-bottomed flask. Theresulting solution is then heated at 50 C for 3-4 hours, the reactionwas complete, and the resulting solution was cooled to room temperature,and passed through a short pad of silicagel. The product obtained wascrystallized from a mixture of hexane and dichloromethane. Yield: 90%.

5. 2-(Cyclopentylethyl)-6-(3,4,5-trifluorophenyl)naphthalene (Compound5)

To a solution of compound 4 in ethyl acetate was added a catalyticamount (5 wt %) of 5% Pd-C, the resulting solution was continuedstirring vigorously until the reaction was complete. The productobtained was crystallized from hexane. Yield 92%.

Incorporation of Deuterium into Structures:

Methods of incorporating one or more deuterium atoms into a structureare known in the art.

Characterization methods and property analysis of compounds and mixturesare well-known in the art. Methods to alter the material properties of amixture, such as adding other compound to a mixture, or by adding moreor less of a compound in a mixture, are also known in the art.

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; and non-patent literature documents or other sourcematerial; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

All patents and publications mentioned in the specification areindicative of the levels of skill of those skilled in the art to whichthe invention pertains. References cited herein are incorporated byreference herein in their entirety to indicate the state of the art, insome cases as of their filing date, and it is intended that thisinformation can be employed herein, if needed, to exclude (for example,to disclaim) specific embodiments that are in the prior art. Forexample, when a compound is claimed, it should be understood thatcompounds known in the prior art, including certain compounds disclosedin the references disclosed herein (particularly in referenced patentdocuments), are not intended to be included in the claim and areintended to be able to be removed individually or collectively.

When a group of substituents is disclosed herein, it is understood thatall individual members of those groups and all subgroups, including anyisomers and enantiomers of the group members, and classes of compoundsthat can be formed using the substituents are disclosed separately. Whena Markush group or other grouping is used herein, all individual membersof the group and all combinations and subcombinations possible of thegroup are intended to be individually included in the disclosure.

Every formulation or combination of components described or exemplifiedcan be used to practice the invention, unless otherwise stated. Specificnames of compounds are intended to be exemplary, as it is known that oneof ordinary skill in the art can name the same compounds differently.When a compound is described herein such that a particular isomer orenantiomer of the compound is not specified, for example, in a formulaor in a chemical name, that description is intended to include eachisomers and enantiomer of the compound described individual or in anycombination. One of ordinary skill in the art will appreciate thatmethods, device elements, starting materials, synthetic methods, andmixture constituents other than those specifically exemplified can beemployed in the practice of the invention without resort to undueexperimentation. All art-known functional equivalents, of any suchmethods, device elements, starting materials, synthetic methods, andmixture constituents are intended to be included in this invention.Whenever a range is given in the specification, for example, atemperature range, a time range, or a composition range, allintermediate ranges and subranges, as well as all individual valuesincluded in the ranges given are intended to be included in thedisclosure.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim element. As used herein, “consisting essentiallyof” does not exclude materials or steps that do not materially affectthe basic and novel characteristics of the claim. Any recitation hereinof the term “comprising”, particularly in a description of components ofa composition or in a description of elements of a device, is understoodto encompass those compositions and methods consisting essentially ofand consisting of the recited components or elements. The inventionillustratively described herein suitably may be practiced in the absenceof any element or elements, limitation or limitations which is notspecifically disclosed herein.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments and optional features, modification and variation of theconcepts herein disclosed may be resorted to by those skilled in theart, and that such modifications and variations are considered to bewithin the scope of this invention as defined by the appended claims.

In general the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. Thedefinitions are provided to clarify their specific use in the context ofthe invention.

One skilled in the art would readily appreciate that the presentinvention is well adapted to carry out the objects and obtain the endsand advantages mentioned, as well as those inherent therein. The liquidcrystal compounds and methods described herein as presentlyrepresentative of preferred embodiments are exemplary and are notintended as limitations on the scope of the invention. Changes thereinand other uses will occur to those skilled in the art, which areencompassed within the spirit of the invention, are defined by the scopeof the claims.

Although the description herein contains many specificities, theseshould not be construed as limiting the scope of the invention, but asmerely providing illustrations of some of the embodiments of theinvention. Thus, additional embodiments are within the scope of theinvention and within the claims. All references cited herein are herebyincorporated by reference to the extent that there is no inconsistencywith the disclosure of this specification. Some references providedherein are incorporated by reference herein to provide detailsconcerning additional starting materials, additional methods ofsynthesis, additional methods of analysis and additional uses of theinvention.

1. A compound having the formula:

wherein R is selected from the group consisting of H and unsubstitutedor substituted alkyl each having 1-12 carbon atoms wherein thesubstitutions are independently one or more of halogen or CN, whereinone or more CH₂ groups of the alkyl groups may independently be replacedwith —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O— or —CH═CH—, provided thatheteroatoms are not connected directly, except as permitted in thelisted groups; A and B are each independently selected from the groupconsisting of: 1,4-cyclohexyl, in which one CH2 or two not directlylinked CH2 can be replaced by O or S; 1,4-cyclohexenyl;piperidine-1,4-diyl; 1,4-bicyclo[2,2,2]octylene; 1,4-phenyl, which maybe substituted with one or more halogens; Pyridin-5,2-dyl;pyrimidin-5,2-diyl; naphthalene-2,6-diyl;trans-decahydronaphthalene-2,6-diyl; tetrahydronaphthalene-2,6-diyl;indane; indene; phenanthryl; and dibenzofuran, which may eachindependently in each instance be independently substituted with one ormore halogens and/or one or more X1-X4 substitutents; Z1 is a singlebond or C1-7 unsubstituted or substituted alkylene, wherein thesubstitutions are independently one or more of halogen or CN, whereinone or more CH₂ groups of the alkyl groups may each independently bereplaced by —O—, —S—, —CO—O—, —O—CO—, —O—CO—O— or —CH═CH— provided thatheteroatoms are not connected directly to each other except as permittedin the listed groups; Z2 and Z3 are each independently selected from thegroup consisting of: a single bond, —(CH₂)₂—, —(CH₂)₄—, —CH═CHCH₂CH₂—,—CH₂CH₂CH═CH—, CF₂O, OCF₂, CF₂CF₂, CF═CF, CH₂CF₂, CF₂CH₂, OCF2CF2O,C2H4CF2O, CH2CF2OCH2, CH2OCF2CH2, OCF2C2H4, C3H6O, OC3H6, C2H4OCH2,CH2OC2H4, CH₂O, OCH₂, —CH═CH—, —C≡C—, and COO; n, m and K are eachindependently 0, 1, or 2, and m+K+n≧2; X1, X2, X3, and X4 are eachindependently selected from the group consisting of: H, F, Cl, CF3,CHF2, OCF3, OCF2H and CN; Y is independently selected from the groupconsisting of: H, F, Cl, CN, NCS, OCHF₂, CHF₂, OCF₃, OCF2CF3, CF₃, C₁₋₂₀alkyl, C₁₋₂₀ alkoxy, C₁₋₂₀ alkenyl, and C₁₋₂₀ alkenyloxy, wherein thealkyl, alkoxy, alkenyl, and alkenyloxy groups may be independentlysubstituted by one or more halogens; wherein one or more hydrogen atomsin Formula I may be replaced with deuterium; provided that when R═H andY has less than 2 carbon atoms and X3, X4 are H or when R═H and Y hastwo or more carbon atoms and Z1 has more than 3 carbon atoms, there mustbe a fused ring system present in the compound or one of Z1, Z2 and Z3must be selected from the group consisting of: C1-C3 alkylene,—CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—, CF₂O, OCF₂, CF₂CF₂, CF═CF, CH₂CF₂, CF₂CH₂,OCF2CF2O, C2H4CF2O, CH2CF2OCH2, CH2OCF2CH2, OCF2C2H4, C3H6O, OC3H6,C2H4OCH2, CH2OC2H4, and —CH═CH—; and provided that when R is not H and Ydoes not contain a —CF2- group, either one of A and B is selected fromthe group consisting of: 1,4-cyclohexene, in which one or two notdirectly linked CH2 groups can be replaced by O or S; Pyridin-5,2-dyl;pyrimidin-5,2-diyl; indane; indene; phenanthryl, and dibenzofuran; orone of Z1, Z2 and Z3 must be selected from the group consisting of:—(CH₂)₄—, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—, CF₂O, OCF₂, CF₂CF₂, CF═CF,CH₂CF₂, CF₂CH₂, OCF2CF2O, C2H4CF2O, CH2CF2OCH2, CH2OCF2CH2, OCF2C2H4,C3H6O, OC3H6, C2H4OCH2, CH2OC2H4, —CH═CH—, and —C≡C—.
 2. The compound ofclaim 1 having a positive dielectric constant.
 3. A compound of claim 2,having formula I-1 through I-17 as shown herein.
 4. The compound ofclaim 1 having a negative dielectric constant.
 5. The compound of claim4, having formula I-18 through I-47 as shown herein.
 6. A liquid crystalmixture having positive dielectric constant comprising a compound ofclaim
 1. 7. The mixture of claim 6, wherein the mixture furthercomprises at least one compound of formula II-XVI as shown herein. 8.The mixture of claim 6, wherein the mixture further comprises at leastone compound of formula XVII-XXIII as shown herein.
 9. The mixture ofclaim 6, wherein the mixture comprises at least one compound of formulaII-XVI as shown herein and at least one compound of formula XVII-XXIIIas shown herein.
 10. A liquid crystal mixture having negative dielectricconstant comprising a compound of claim
 1. 11. The mixture of claim 10,wherein the mixture further comprises at least one compound of formulaXXIV-XLIV as shown herein.
 12. The mixture of claim 10, wherein themixture further comprises at least one compound of formula XLV-XLVIII asshown herein.
 13. The mixture of claim 10, wherein the mixture furthercomprises at least one compound of formula XXIV-XLIV as shown herein andat least one compound of formula XLV-XLVIII as shown herein.
 14. Adevice comprising a compound of claim
 1. 15. A device comprising amixture of claim
 4. 16. The compound of claim 1, wherein one or morehydrogen atoms in any ring is substituted with deuterium.
 17. Thecompound of claim 1, wherein one or more hydrogen atoms in any non-ringstructure is substituted with deuterium.